Back to EveryPatent.com
| United States Patent |
6,046,349
|
|
Batz-Sohn
, et al.
|
April 4, 2000
|
Oligomeric organosilicon compounds, their use in rubber mixtures and for
the production of shaped articles
Abstract
Oligomeric organosilicon compounds are disclosed of the formula I
##STR1##
wherein R.sup.1, R.sup.2, R.sup.3 independently of one another denote H,
(C.sub.1 -C.sub.4)alkyl, (C.sub.1 -C.sub.4) alkoxy, (C.sub.1 -C.sub.4)
haloalkoxy, (C.sub.1 -C.sub.4)haloalkyl, phenyl, aryl or aralkyl and
Z denotes an alkylidene radical having 0-6 carbon atoms, x can be a
statistical average of 1-6 and
n=1-150 and . . . means that z can be bonded either to the one or the other
C atom, and the particular free valency is occupied by a hydrogen.
and their use in rubber mixtures and for the production of shaped articles,
in particular pneumatic tires.
| Inventors:
|
Batz-Sohn; Christoph (Hanau, DE);
Luginsland; Hans-Detlef (Koln, DE)
|
| Assignee:
|
Degussa-Huels Aktiengesellschaft (Frankfurt, DE)
|
| Appl. No.:
|
343397 |
| Filed:
|
June 30, 1999 |
Foreign Application Priority Data
| Jul 01, 1998[DE] | 198 29 390 |
| Current U.S. Class: |
556/427; 152/151; 523/209; 523/213; 523/215; 523/216; 524/155; 524/262; 524/265; 525/102; 525/342; 525/351; 525/352; 556/426 |
| Intern'l Class: |
C07F 007/08; C08K 009/06; C08K 005/24 |
| Field of Search: |
556/426,427
152/151
523/209,213,216
525/102,342,351,352
524/155,262,265
|
References Cited
U.S. Patent Documents
| 3344161 | Sep., 1967 | Moedritzer et al. | 556/427.
|
| 5587503 | Dec., 1996 | Heider et al. | 556/427.
|
| 5936112 | Aug., 1999 | Gobel et al. | 556/427.
|
| 5977225 | Nov., 1999 | Scholl et al. | 524/262.
|
| Foreign Patent Documents |
| 2212239 | Oct., 1973 | DE.
| |
| 3823450 | Feb., 1990 | DE.
| |
Primary Examiner: Shaver; Paul F.
Attorney, Agent or Firm: Smith, Gambrell & Russell, LLP
Claims
We claim:
1. An oligomeric organosilicon compound of the formula I
##STR4##
wherein R.sup.1, R.sup.2, R.sup.3 independently of one another denote H,
(C.sub.1 -C.sub.4) alkyl, (C.sub.1 -C.sub.4) alkoxy, (C.sub.1 -C.sub.4)
haloalkoxy, (C.sub.1 -C.sub.4) haloalkyl, phenyl, aryl or aralkyl and Z
denotes alkylidene having 0-60 carbon atoms, x is a statistical average of
1-6 and n=1-150 and the designation . . . means that Z can be bonded
either to the one or the other C atom, and the particular free valency is
occupied by a hydrogen.
2. The oligomeric organosilicon compound according to claim 1, wherein
R.sup.1, R.sup.2, R.sup.3 =ethoxy, Z.dbd.CH.sub.2 CH.sub.2 and x=1.
3. The oligomeric organosilicon compound according to claim 1 wherein n=20
to 130.
4. The oligomeric organosilicon compound according to claim 2 wherein n=20
to 130.
5. The oligomeric organosilicon compound according to claim 1 wherein n=50
to 100.
6. The oligomeric organosilicon compound according to claim 2 wherein n=50
to 100.
7. A process for the preparation of the oligomeric organosilicon compound
according to claim 1 comprising reacting a compound of the formula II
##STR5##
wherein R.sup.1, R.sup.2, R.sup.3 Z and . . . have the given meaning and X
is halogen, with MSH or M.sub.2 S.sub.y
wherein
M is a metal ion and y is a statistical average with a number between 2 and
6, or
with M.sub.2 S and S, wherein M is a metal ion, optionally in a solvent and
optionally at reaction temperatures between 20.degree. C. and 150.degree.
C. and optionally under catalytic conditions under pressures between
normal pressure or an increased pressure of up to 6 bar, to yield a
compound of the formula I.
8. The process according to claim 7, wherein the metal ion is an ammonium
ion, sodium ion or potassium ion.
9. The oligomeric organosilicon compound obtainable by a process according
to claim 7.
10. The oligomeric organosilicon compound obtainable by a process according
to claim 8.
11. A rubber mixture comprising an oligomeric organosilicon compound mixed
with a rubber according to claim 1.
12. A rubber mixture according to claim 11, wherein the organosilicon
compound is present in an amount of 0.1 to 15 wt. %, based on the amount
of filler employed.
13. A rubber mixture according to claim 11, wherein the organosilicon
compound is present in an amount of 5 to 10 wt. %, based on the amount of
filler employed.
14. A rubber mixture according to claim 11 comprising a synthetic rubber
and silica as the filler.
15. A process for the preparation of a rubber mixture comprising mixing a
rubber, at least one filler and an oligomeric organosilicon compound
according to claim 1 together to form a rubber mixture.
16. A shaped article obtainable from a rubber mixture according to claim
11.
17. The shaped article according to claim 16, which is a pneumatic tire.
18. The shaped article according to claim 16, which is a tire tread.
19. A process for using a rubber mixture for the production of a shaped
article, comprising selecting a rubber formulation meeting the desired
characteristics for the shaped article, mixing said rubber with the
compound of claim 1 to form a rubber mixture and molding said mixture into
the desired shape.
20. A process for forming a shaped article of rubber comprising selecting
the rubber mixture of claim 11, shaping it into the desired confirmation
and vulcanizing said rubber to form the desired article.
21. An oligomeric organosilicon compound according to claim 1 deposited on
an inert inorganic or organic support.
22. The oligomeric organosilicon compound according to claim 1 deposited on
carbon black or silica as a support.
23. The rubber mixture according to claim 11 wherein said rubber is a
naturally occurring rubber or synthetic rubber.
24. The rubber mixture according to claim 11 which is unvulcanized.
25. The rubber mixture according to claim 11 which is vulcanized.
Description
INTRODUCTION AND BACKGROUND
The present invention relates to new oligomeric organosilicon compounds, a
process for their preparation and their use in rubber mixtures and for the
production of shaped articles.
It is known to employ sulfur-containing organosilicon compounds, such as
3-mercaptopropyltrimethoxysilane or bis-(3-[triethoxysilyl]-propyl)
tetrasulfane, as a silane adhesion promoter or reinforcing additive in
rubber mixtures with an oxidic filler content, inter alia for treads and
other components of car tires (DE 2 141 159, DE 2 212 239, U.S. Pat. Nos.
3,978,103, 4,048, 206).
It is furthermore known that sulfur-containing silane adhesion promoters
are employed in the preparation of sealing compositions, casting moulds
for metal casting, paint and protective coating films, adhesives, asphalt
mixtures and plastics with an oxidic filler content.
Finally, there are possible uses for these compounds in the fixing of
active compounds and functional units on inorganic support materials, e.g.
in the immobilization of homogenous catalysts and enzymes, in the
preparation of fixed bed catalysts and in liquid chromatography.
It is furthermore known that the formation of rubber mixtures with
longer-chain polysulfanes, in particular bis-(3-[triethoxysilyl]-propyl)
tetrasulfane, chiefly used for adhesion promotion in such rubber mixtures
with an oxidic filler content requires particular care during the
processing with the rubber, in order to avoid prevulcanization during
mixing of the components. The use of organosilanes with shorter
polysulfane chains, in particular with disulfane units, which is
advantageous in this respect, has been described in respect of the
processing and properties of the vulcanization products in EP-A 0732 362
(corresponding to U.S. Pat. No. 5,580,919) and by Panzer (L. Panzer, Am.
Chem. Soc., Rubber Div. Meeting 1997). However, a shortening of the
polysulfane chains has the effect of an undesirable, lower crosslinking
yield between the oxidic filler and the rubber polymer.
DD 262 231 A1 and EP-B1 0 466 066 describe sulfur-rich, oligomeric
organoorganooxysilanes with a cycloalkenyl unit which have the
disadvantage, however, that their use as a silane adhesive or reinforcing
additive leads to vulcanized products with rather average static and
dynamic properties, in particular in tensile strength, breaking energy and
tensile stress. Moreover, the preparation of this type of compound is
complicated and expensive.
It has now been found that the abovementioned disadvantages of the prior
art can be substantially avoided by the use of the new oligomeric
organosilicon compounds according to the invention as an adhesion promoter
or reinforcing additive in rubber mixtures.
SUMMARY OF THE INVENTION
The present invention accordingly relates to new oligomeric organosilicon
compounds of the formula I
##STR2##
wherein R.sup.1, R.sup.2, R.sup.3 independently of one another denote H,
(C.sub.1 -C.sub.4) alkyl, (C.sub.1 -C.sub.4)alkoxy, (C.sub.1
-C.sub.4)haloalkoxy, (C.sub.1 -C.sub.4)haloalkyl, phenyl, aryl or aralkyl
and
Z denotes alkylidene having 0-6 carbon atoms, x can be a statistical
average of 1-6 and
n=1-150 and the designation . . . means that Z can be bonded either to the
one or the other C atom, and the particular free valency is occupied by a
hydrogen.
Preferred embodiments of the oligomeric organosilicon compounds according
to the invention are set forth below together with a description of the
process of the invention and products according to the invention.
Thus, organosilicon compounds in which R.sup.1, R.sup.2 and R.sup.3
=ethoxy, Z.dbd.CH.sub.2 CH.sub.2 and x=1 are particularly suitable for the
use according to the invention.
The oligomeric organosilicon compounds according to the invention as
described herein can be cyclic, branched or linear in structure. Preferred
compounds are those in which n=20 to 130, particularly preferably n=50 to
100.
The compounds according to the invention can be present both as an
individual compound with a defined molecular weight, and as an oligomer
mixture with a molecular weight distribution. For process technology
reasons, it is as a rule easier to prepare and adopt oligomer mixtures.
DETAILED DESCRIPTION OF THE INVENTION
The preparation of the compounds of the general formula I according to the
invention can be carried out easily and in an advantageous manner by a
procedure in which compounds of the formula II
##STR3##
wherein R.sup.1, R.sup.2 and R.sup.3 and the designation . . . have the
above-mentioned meaning, X can be halogen,
are reacted with MSH or M.sub.2 S.sub.y, wherein M is a metal ion and y is
a statistical average with a number between 2 and 6 or with M.sub.2 S and
S, wherein M is a metal ion, optionally in a solvent and optionally at
reaction temperatures between 20.degree. C. and 150.degree. C. and
optionally under catalytic conditions under pressures between normal
pressure or an increased pressure of up to 6 bar, to give compounds of the
formula I.
The following procedure is advantageously used for the preparation of the
new compounds. A compound of the formula II wherein R.sup.1, R.sup.2 and
R.sup.3, X, Z and . . . have the abovementioned meaning is added to a
suspension of MSH or M.sub.2 S and S, or preciously prepared M.sub.2
S.sub.y, in a suitable inert solvent or mixtures thereof, such as, for
example, in an aromatic solvent, such as chlorobenzene, a halogenated
hydrocarbon, such as chloroform, methylene chloride, an ether, such as
diisopropyl ether, tert-butyl methyl ether, tetrahydrofuran or diethyl
ether, acetonitrile or carboxylic acid esters, for example ethyl acetate,
methyl acetate or isopropyl acetate, an alcohol, for example methanol,
ethanol, n-propanol, i-propanol, n-butanol, se-butanol or tert-butanol.
The mixture is heated for 1 to 24 h, preferably 1 to 8 h under normal
pressure or an increased pressure of up to 6 bar, preferably under normal
pressure, at temperatures between 20.degree. C. and 150.degree. C.,
preferably at 35.degree. C. to 80.degree. C., particularly preferably at
55.degree. C. to 65.degree. C., and after the reaction has ended, the
precipitate formed is filtered off. After removal of the solvent, the new
compounds of the type I as a rule remain as viscous liquids.
Ethanol is used as the particularly preferred solvent. The reactions are
advantageously carried out under absolute conditions, i.e. under exclusion
of moisture. It is therefore advisable to use predried solvents, such as,
for example, analytical grade ethanol.
Ammonium ions, sodium ions or potassium ions are used as preferred metal
ions M. The use of the corresponding sodium compound is particularly
suitable here.
Various processes of the type described above for sulfidization are known
and are described in JP 722 8588, U.S. Pat. Nos. 5,405,985 and 5,466,848.
The US patents are relied on and incorporated herein by reference. The
reaction can be carried out under catalysis. The catalyst can be employed
herein catalytic or stoichiometric amounts.
The compounds of the type II are obtained here starting from the
corresponding unsaturated compounds, analogously to DD 262 331A1 or EP-A2
0 350 600. The unsaturated compounds can be obtained as described in EP-A2
0 350 600, relied on herein and incorporated by reference or in an
analogous manner.
The compounds of the general type II can also be obtained directly from the
corresponding unsaturated compounds in accordance with EP-B1 0 446 066.
This patent is expressly relied on, and the content of this patent is
intended to be subject matter of the present disclosure and is
incorporated herein by reference. The term "alkyl" is to be understood as
meaning both "straight-chain" and "branched" alkyl groups. The term
"straight-chain alkyl group" is to be understood as meaning, for example,
groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl,
"branched alkyl group" is to be understood as meaning groups such as, for
example, isopropyl or tert-butyl. The term "halogen" represents fluorine
chlorine, bromine or iodine. The term "alkoxy" represents groups such as,
for example, methoxy, ethoxy, propoxy, butoxy, isopropoxy, isobutoxy or
pentoxy.
"Aryl" is the context according to the invention is to be understood as
meaning (C.sub.1 -C.sub.6)alkyl-, (C.sub.1 -C.sub.6)alkoxy-, halogen- or
heteroatom-, such as N-, O-, P- or S-substituted phenyls, biphenyls or
other benzoid compounds. "Arylalkyl" is to be understood as meaning that
the "aryls" described above are bonded to the corresponding silicon atom
via a (C.sub.1 -C.sub.6)alkyl chain, which in turn can be (C.sub.1
-C.sub.4)alkyl- or halogen-substituted. If "aryl" has heteroatom, such as
O or S, the (C.sub.1 -C.sub.6)alkyl chain can then also establish a bond
with the silicon atom via the heteroatom.
When defining the substituents, such as e.g. (C.sub.1 -C.sub.4) alkoxy, the
number in the index designates the number of all the carbon atoms in the
radical.
The preparation of the oligomeric organosilicon compounds according to the
invention is shown by way of example in examples 1 and 2.
The oligomeric organosilicon compounds thus obtained in a simple manner are
surprisingly particularly suitable for use in rubber mixtures.
Rubber mixtures which comprise the organosilicon compounds according to the
invention as an adhesion promoter or reinforcing additive and shaped
articles resulting after a vulcanization step, in particular pneumatic
tires or tire treads, have, after carrying out the processes according to
the invention, a low rolling resistance with simultaneously good adhesion
in the wet and high abrasion resistance.
The present invention therefore provides rubber mixtures comprising rubber,
filler, in particular also precipitated silica and optionally further
rubber auxiliary substances, and at least one organosilicon compound
according to the invention which is built up from the structure set forth
in claim 1 and which is employed in amounts of 0.1 to 15 wt. %,
particularly preferably 5-10 wt. %, based on the amount of the oxidic
filler employed.
When the organosilicon compounds claimed are used in rubber mixtures,
advantages are found in the static and dynamic data of the vulcanization
products compared with the mixtures according to the prior art (cf. table
4). This manifests itself in particular in a higher tensile strength,
breaking energy and a higher 300% stress value. Moreover, the mixture with
the organosilicon compounds claimed shows a reduced build up of heat
(Goodrich flexometer test), which indicates positive hysteresis
properties.
The organosilicon compounds according to the invention and the fillers are
preferably added at material temperatures of 100 to 200.degree. C. but
they can also be added later at lower temperatures (40 to 100.degree. C.),
e.g. together with further rubber auxiliary substances.
The organosilicon compounds according to the invention can be added to the
mixing process either in the pure form or in a form absorbed on an inert
organic or inorganic support. Preferred support materials are silicas,
naturally occurring or synthetic silicates, aluminum oxide or carbon
blacks.
Possible fillers for the rubber mixtures according to the invention are:
Carbon blacks: the carbon blacks to be used here are prepared by the flame
black, furnace black or gas black process and have BET surface areas of 20
to 200 m.sup.2 /g. The carbon blacks can optionally also contain
heteroatoms, such as e.g. Si.
highly disperse silicas, prepared e.g. by precipitation of solutions of
silicates or flame hydrolysis of silicon halides with specific surface
areas of 5 to 1000, preferably 20 to 400 m.sup.2 /g (BET surface area) and
with primary particle sizes of 10 to 400 nm. The silicas can optionally
also be present as mixed oxides with other metal oxides, such as Al, Mg,
Ca, Ba, Zn and titanium oxides.
Synthetic silicates, such as aluminum silicate, alkaline earth metal
silicates, such as magnesium silicate or calcium silicate, with BET
surface areas of 20 to 400 m.sup.2 /g and primary particle diameters of 10
to 400 nm.
Naturally occurring silicates, such as kaolin and other naturally occurring
silicas.
Glass fibers and glass fiber products (mats, strands) or glass microbeads.
Preferably, carbon blacks with BET surface areas of 20 to 400 m.sup.2 /g or
highly disperse silicas, prepared by precipitation of solutions of
silicates, with BET surface areas of 20 to 400 m.sup.2 /g are employed, in
amounts of 5 to 150 parts by wt., in each case based on 100 parts of
rubber.
The fillers mentioned can be employed by themselves or as a mixture. In a
particularly preferred embodiment of the process, 10 to 150 parts by wt.
of light-coloured fillers, optionally together with 0 to 100 parts by wt.
of carbon black, and 0.1 to 15 parts by wt., preferably 5 to 10 parts by
wt. of a compound of the formula (I), in each case based on 100 parts by
wt. of the filler employed, are employed for the preparation of the
mixtures.
In addition to naturally occurring rubber, synthetic rubbers are also
suitable for the preparation of the rubber mixtures according to the
invention. Preferred synthetic rubbers are described, for example, in W.
Hofmann, Kautschuktechnologie [Rubber Technology], Genter Verlag,
Stuttgart 1980. They include, inter alia,
polybutadiene (BR)
polyisoprene (IR)
styrene/butadiene copolymers with styrene contents of 1 to 60, preferably 2
to 50 wt. % (SBR)
isobutylene/isoprene copolymers (IIR)
butadiene/acrylonitrile copolymers with acrylonitrile contents of 5 to 60,
preferably 10 to 50 wt. % (NBR)
partly hydrogenated or completely hydrogenated NBR rubber (HNBR)
ethylene/propylene/diene copolymers (EPDM)and mixtures of these rubbers.
Anionically polymerized L-SBR rubbers with a glass transition temperature
above -50.degree. C. and mixtures thereof with diene rubbers are of
particular interest for the production of motor vehicle tires.
The rubber vulcanization products according to the invention can comprise
further rubber auxiliary products, such as reaction accelerators,
antioxidants, heat stabilizers, light stabilizers, anti-oxonants,
processing auxiliaries, plasticizers, tackifiers, blowing agents,
dyestuffs, waxes, extenders, organic acids, retardants, metal oxides and
activators, such as triethanolamine, polyethylene glycol, hexanetriol,
which are known to the rubber industry.
The rubber auxiliaries are employed in conventional amounts, which depend,
inter alia, on the intended use. Conventional amounts are e.g. amounts of
0.1 to 50 wt. %, based on the rubber. The oligomeric silanes can be used
by themselves as crosslinking agents. As a rule, the addition of further
crosslinking agents is advisable. Sulfur or peroxides can be employed as
further known crosslinking agents. The rubber mixtures according to the
invention can furthermore comprise vulcanization accelerators. Examples of
suitable vulcanization accelerators are mercaptobenzothiazoles,
sulfenamides, guanidines, thiurams, dithicarbamates, thioureas and
thiocarbonates. The vulcanization accelerators and sulfur or peroxides are
employed in amounts of 0.1 to 10 wt. %, preferably 0.1 to 5 wt. %, based
on the rubber.
The vulcanization of the rubber mixtures according to the invention can be
carried out at temperatures of 100 to 200.degree. C., preferably 130 to
180.degree. C., optionally under a pressure of 10 to 200 bar. The mixing
of the rubbers with the filler, optionally rubber auxiliary substances and
the silanes according to the invention can be carried out in conventional
mixing units, such as rolls, internal mixers and mixing extruders. The
rubber vulcanization products according to the invention are suitable for
the production of shaped articles, e.g. for the production of pneumatic
tires, tire treads, cable sheathings, hoses, drive belts, conveyor belts,
roller coverings, tires, shoe soles, sealing rings and damping elements.
The preparation of the rubber mixtures and of the vulcanization products is
described by way of example in examples 3 and 5. The superior properties
of the compounds according to the invention compared with the prior art
(comparison examples 3 and 5) are shown with the aid of example 4, which
uses an oligomeric organosilicon compound according to the invention as
the adhesion promoter.
EXAMPLES 1-2
Preparation of the Organosilanepolysulfanes
Example 1
1. 86 g Na.sub.2 S and 35.0 g sulfur are suspended in 1.50 l ethanol and
the mixture is head to 60.degree. C. 289 g (1.00 mol) 3,
4-dichlorobutyltriethoxysilane are then added dropwise and the mixture is
headed under reflux for 5 h. Thereafter, it is allowed to cool and the
NaCl formed is filtered off. After removal of the solvent by distillation,
225 g (80% of theory) of the compound of the formula I where R.sup.1
=EtO), R.sup.2 =EtO, R.sup.3 =EtO, Z.dbd.CH.sub.2 --CH.sub.2, x=1 remain.
Analysis values:
Calculated C 42.52 H 7.85 S 22.7
Found C 42.70 H 7.92 S 22.52
Example 2
2. 86 g Na.sub.2 S and 71.0 g sulfur are suspended in 1.50 l ethanol and
the mixture is heated to 60.degree. C. 289 g (1.00 mol) 3,
4-dichlorobutyl-triethoxysilane are then added dropwise and the mixture is
heated under reflux for 5 h. Thereafter, it is allowed to cool and the
NaCl formed is filtered off. After removal of the solvent by distillation,
245 g (78% of theory) of the compound of the formula I where R.sup.1 =EtO,
R.sup.2 =EtO, R.sup.3 =EtO, Z.dbd.CH.sub.2 CH.sub.2, x=1.45 remain.
Analysis values:
Calculated C 40.45 H 7.47 S 26.46
Found C 40.70 H 7.56 S 26.3
Examples 3-5
Preparation of the Rubber Mixtures and Vulcanization Products
General Procedure Instructions
The recipe used for the rubber mixtures is given in the following table 1.
The unit phr here means parts by weight per 100 parts of the crude rubber
employed.
TABLE 1
______________________________________
Substance Amount [phr]
______________________________________
1.sup.st stage
Buna VSL 5025-1 96.0
Buna CB 24 30.0
Ultrasil VN3 80.0
ZnO 3.0
Stearic acid 2.0
Naftolene ZD 10.0
Vulkanox 4020 1.5
Protector G35P 1.0
TESPT 6.4
2.sup.nd stage
Batch stage 1
3.sup.rd stage
Batch stage 2
Vulkacit D 2.0
Vulkacit CZ 1.5
Sulfur 1.5
______________________________________
The polymer VSL 5025-1 is an SBR copolymer from Bayer AG polymerized in
solution and having a styrene content of 25 wt. % and a butadiene content
of 75 wt. %. Of the butadiene 73% is linked as 1, 2, 10% as cis-1, 4 and
17% as trans-1,4. The copolymer comprises 37.5 phr oil and has a Mooney
viscosity (ML 1+4/100.degree. C.) of 50.+-.5.
The polymer Buna CB 24 is a cis-1, 4-polybutadiene (Neodym type) from Bayer
AG with a cis-1, 4 content of 97%, a trans-1, 4 content of 2%, a 1,2
content of 1% and a Mooney viscosity of between 39 and 49.
The silica VN3 from Degussa-Huls AG has a BET surface area of 175 m.sup.2
/g. Bis-(3-[triethoxysilyl]-propyl) tetrasulfane (TESPT) is marketed under
the trade name SI 69 by Degussa-Huls AG.
Naftolene ZD from Chemetall was used as the aromatic oil; Vulkanox 4020 is
PPD from Bayer AG, and Protrector G35P is an anti-ozonant wax from
HB-Fuller GmbH. Vulkacit D (DPG) and Vulkacit CZ (CBS) are commercial
products from Bayer AG.
The rubber mixture is prepared in three stages in an internal mixer in
accordance with the following tabular list:
TABLE 2
______________________________________
Stage 1
Settings
Mixing unit Werner & Pfleiderer
Friction 1:1.11
Speed 70 min.sup.-1
Plunger 5.5 bar
pressure
Empty volume 1.6 L
Filling level 0.55
Flow temp. 70.degree. C.
Mixing
operation
0 to 1 min Buna VSL 5025-1 + Buna CB 24
1 to 3 min 1/2 Ultrasil VN3, ZnO, stearic acid, Naftolen
ZD, silane
3 to 4 min 1/2 Ultrasil VN3, Vulkanox 4020, Protector G35P
4 min clean
4 to 5 min mix
5 min clean
5 to 6 min mix and deliver
Batch temp 140-150.degree. C.
Storage 24 h at room temperature
Stage 2
Settings
Mixing unit as in stage 1 except:
Speed 80 min.sup.-1
Filling level 0.53
Flow temp. 90.degree. C.
Mixing
operation
0 to 2 min break up batch stage 1
2 to 5 min maintain batch temperature 150.degree. C. by varying
speed
5 min deliver
Batch temp. 150-155.degree. C.
Storage 4 h at room temperature
Stage 3
Settings
Mixing unit as in stage 1 except
Speed 40 min.sup.-1
Filling level 0.51
Flow temp. 50.degree. C.
Mixing
operation
0 to 2 min Batch stage 2 + Vulkacit CZ + Vulkacit D +
sulfur
2 min deliver and form skin on laboratory roll mill
(diameter 200 mm, length 450 mm, flow
temperature 50.degree. C.)
Homogenization:
cut in 3* left, 3* right and fold over, and
turn over 8* for a narrow roll nip (1 mm) and
3* for a wide roll nip (3.5 mm) and then draw
out a skin
Batch temp 90-100.degree. C.
______________________________________
The general process for the preparation of rubber mixtures and
vulcanization products thereof is described in the following: "Rubber
Technology Handbook", W. Hofmann, Hanser Verlag 1994. The vulcanization
time for the test specimens is 60 minutes at 165.degree. C.
The rubber testing is carried out in accordance with the test methods
described in table 3.
TABLE 3
______________________________________
Pysical testing Standard/Conditions
______________________________________
ML 1 + 4, 100.degree. C.
DIN 53523/3 ISO 667
Vulkameter test, 165.degree. C. DIN 53529/3, ISO 6502
Tensile test on ring, DIN 53504, ISO 37
23.degree. C.
Tensile strength
Tensile values
Elongation at break
Shore A hardness, 23.degree. C. DIN 53 505
Ball rebound, 0 and 60.degree. C. ASTM D 5308
Viscoelastic properties, DIN 53 513, ISO 2856
0 and 60.degree. C., 16 Hz, 50N
preliminary force and 25N
amplitude force
Complex modulus E*,
Loss factor tan .delta.
Goodrich flexometer, 25 DIN 53 533, ASTM D 623 A
min at 23.degree. C. and 0.175
inch stroke
DIN abrasion, 10N force DIN 53 516
Dispersion ISO-DIS 11345
______________________________________
Examples 3, 4 and 5
Examples 3 (comparison example), 4 and 5 (comparison example) are carried
out in accordance with the general procedure instructions.
In a modification to comparison example 3, instead of
bis(3-[triethoxysilyl]-propyl) tetrasilane (TESPT) the organosilicon
compound from example 1 is added to the mixture. Example 5 is also a
comparison example, and instead of TESPT contains the oligomeric
organosilane according to EP-BL 0 466 066. The following rubber data for
the crude mixture and vulcanization product result (table 4):
TABLE 4
______________________________________
Feature: Unit 3 4 5
______________________________________
Crude mixture results
ML (1 + 4), 100.degree. C. 3.sup.rd stage
[MU] 54 57 53
MDR 165.degree. C.
Dmax-Dmin [dNm] 17.56 20.70 19.47
t 10% [min] 1.99 1.66 2.02
t 90% [min] 15.69 42.19 31.89
Vulcanizer results
Tensile test on ring
Tensile strength [MPa] 12.4 14.3 12.8
Tensile value 100% [MPa] 2.0 2.1 1.9
Tensile value 300% [MPa] 10.1 10.8 9.4
Elongation at break [%] 340 360 370
Breaking energy [J] 55.2 67.7 62.3
Shore A hardness (23.degree. C.) [SH] 64 65 66
Ball rebound (0.degree. C.) [%] 11.1 11.6 11.5
Ball rebound (60.degree. C.) [%] 60.4 59.2 56.4
DIN abrasion [mm.sup.3 ] 70 69 87
Viscoelastic testing
Dyn. extension modulus E* [MPa] 26.1 24.3 25.6
(0.degree. C.)
Dyn. extension modulus E* [MPa] 9.4 9.4 9.4
(60.degree. C.)
Loss factor tan .delta. (0.degree. C.) [-] 0.484 0.487 0.491
Loss factor tan .delta. (60.degree. C.) [-] 0.116 0.121 0.129
Goodrich flexometer
Contact temperature [.degree. C.] 46 42 43
Puncture temperature [.degree. C.] 88 83 85
Permanent set [%] 2.5 1.7 1.4
Dispersion [-]- 8 8 8
______________________________________
Further variations and modifications will be apparent to those skilled in
the art from the foregoing and are intended to be encompassed by the
claims appended hereto.
German priority document 198 29 390.9 is relied on and incorporated herein
by reference.
Top